Actuating shaft and method for producing an actuating shaft

ABSTRACT

The invention relates to an actuating shaft ( 1 ), in particular of a suction tube arrangement, with an actuating element ( 8 ) provided for actuating the actuating shaft ( 1 ). It is herein provided that the actuating shaft ( 1 ) has a base body ( 2 ) made of a first material and an actuating shaft body ( 6 ) made of a second material and at least partially applied on the base body ( 2 ), and that the actuating element ( 8 ) is at least partially surrounded by the actuating shaft body. The invention also relates to a method for producing an actuating shaft ( 1 ).

CROSS-REFERENCES TO RELATED APPLICATIONS

This application claims the priority of German Patent Application,Serial No. 10 2010 045 215.7, filed Sep. 13, 2010, pursuant to 35 U.S.C.119(a)-(d), the content of which is incorporated herein by reference inits entirety as if fully set forth herein.

BACKGROUND OF THE INVENTION

The present invention relates to an actuating shaft, in particular of asuction tube arrangement, with an actuating element for operating theactuating shaft. The invention also relates to a method for producing anactuating shaft.

The following discussion of related art is provided to assist the readerin understanding the advantages of the invention, and is not to beconstrued as an admission that this related art is prior art to thisinvention.

Actuating shafts are used, in particular, for suction tube arrangementswhere at least one suction tube opening can be closed and opened with atleast one cover element arranged on the actuating shaft or actuatable bythe actuating shaft. The actuating shaft is typically supported forrotation about a rotation axis. For this purpose, at least one bearingmay be associated with the actuating shaft. The actuating shaft canhereby be moved to an arbitrary rotation angle position within apredetermined angular range. The actuating element which is used toactuate the actuating shaft is provided for this purpose. Typically, adrive cooperates with the actuating element for actuating the actuatingshaft and moving the actuating shaft to the desired rotation angleposition. The actuating element is thus provided to apply the torquefrom the drive to the actuating shaft. For example, the actuatingelement can be operatively connected with the drive by way of a couplinglinkage. The actuating element serves herein as carrier element.

Conventional actuating elements are constructed as ball-shaped headscoupled to a coupling linkage and constructed as a single piece inconjunction with an end section of the shaft of the throttle element.However, this results in a comparatively high manufacturing complexity,because the ball-shaped head is already formed, for example, during andin conjunction with the manufacture of the end section. In addition, acover plate must be formed on the shaft. Several manufacturing steps aretherefore required for producing the throttle element.

It would therefore be desirable and advantageous to obviate prior artshortcomings and to provide an improved actuating shaft which can bemanufactured more cost-effectively.

SUMMARY OF THE INVENTION

According to one aspect of the present invention, an actuating shaft, inparticular of a suction tube arrangement, includes an actuating elementfor actuating the actuating shaft, a base body made of a first material,and an actuating shaft body made of a second material and at leastpartially applied on the base body, said actuating shaft body at leastpartially enclosing the actuating element.

During the manufacture of the actuating shaft, a cover element of theactuating shaft is formed and the actuating element is fastened on theactuating shaft simultaneously. This is attained according to theinvention by constructing the actuating shaft from a base body made of afirst material and an actuating shaft body disposed on the base body andmade of a second material. In addition, the actuating element should beat least partially surrounded by the actuating shaft body. The actuatingshaft thus basically includes a base body, the actuating shaft body andthe actuating element; however, it will be understood that several basebodies, actuating shaft bodies and actuating elements may be present.The base body is made of a first material, for example a metal, inparticular steel. The base body may in principle have any suitableshape, for example be embodied as a substantially straight rod or inform of a crankshaft, wherein in the latter case at least a region ofthe base body is located outside a rotation axis of the actuating shaftor spaced from the rotation axis in the radial direction.

The actuating shaft body is applied on the base body. The actuatingshaft body is made of a second material which preferably is differentfrom the first material. The second material is, for example, a plastic.The actuating shaft body is applied on the base body so that theactuating element is at least partially disposed in the actuating shaftbody, so that the actuating element is held by the actuating shaft bodyand fixed with respect to the base body, in particular with a rotationlock. To attain a particularly torque-proof connection between theactuating element and the base body, the actuating element may have aserration extending in a substantially axial direction in the regionenclosed by the actuating shaft body. The actuating shaft body need notcover the entire base body, but may only be partially disposed on thebase body. It will be understood that an additional layer, for examplemade of an elastomer, maybe deposited on the base body and/or theactuating shaft body, which may operate as a sealing layer to ensurethat the at least one suction tube opening is safely covered by thecover element of the actuating shaft.

According to one advantageous feature of the present invention, at leastone region of the actuating element may at least partiallycircumferentially surround the base body of the actuating shaft. Forthis purpose, the actuating element may have a recess configured to atleast partially receive the base body. To ensure that the actuatingelement is firmly attached on the actuating shaft, the actuating elementmay at least partially surround the base body, while the actuatingelement is in turn surrounded by the actuating shaft body. Surroundingthe actuating element with the base body secures the actuating elementrelative to the base body at least in the radial direction. Surroundingthe actuating element with the actuating shaft body secures theactuating element relative to the base body in the axial direction.Surrounding the actuating element with the actuating shaft body thusprevents the actuating element from sliding off the base body.Preferably, the actuating element completely surrounds the base body inthe circumferential direction.

According to one advantageous feature of the present invention, aclamping connection may be provided between the actuating element andthe base body of the actuating shaft, thereby establishing aparticularly reliable connection between the actuating element and thebase body. The recess with which the base body at least partiallycircumferentially surrounds the actuating element is, for example,centrally formed in the actuating element. The recess may thereby beimplemented as a blind hole, i.e., a hole that does not completelyextend through the actuating element in the axial direction.Alternatively, the recess may also be implemented as a through-opening,with the recess fully extending through the actuating element in theaxial direction.

According to another advantageous feature of the present invention, theactuating element may have a ball-shaped head, wherein the recess atleast partially extends through the ball-shaped head. The ball-shapedhead is hereby disposed on a side of the actuating element facing awayfrom the base body. In particular, the bail-shaped head is used toprovide an operative connection to a drive. For example, the ball-shapedhead may be surrounded at least partially by a coupling linkage which isoperatively connected with the drive.

According to yet another advantageous feature of the present invention,the recess may extend completely through the ball-shaped head. In thisway, an engagement opening may be provided on the side of theball-shaped head facing away from the base body which may be used, forexample, for centering. After the actuating shaft is installed andconnected with the drive, in particular by way of the coupling linkage,the recess or the engagement opening may be closed. This can be done,for example, with a plug which clampingly engages in the engagementopening.

According to yet another advantageous feature of the present invention,the first material may be a metal, in particular steel, and/or thesecond material may be a plastic, in particular a polymer. The actuatingshaft can then be particularly easily manufactured and the actuatingelement can be reliably secured relative to the base body. The firstmaterial is preferably rigid and torsion-proof. The second material ispreferably a moldable material which also adheres to the first material.

According to still another advantageous feature of the presentinvention, a blind hole, in particular a blind hole formed by therecess, may be provided in the ball-shaped head, wherein the bottom ofthe blind hole is defined, in particular, by the base body. The term“blind hole” refers to a recess which does not completely extend throughthe ball-shaped head or the entire actuating element, but instead has abottom. The blind hole may be used, for example, for centering.Advantageously, the blind hole may be formed by the recess. The bottomof the blind hole may be defined by the base body. This means that therecess initially extends completely through the ball-shaped head and/orthe actuating element in the axial direction. The actuating element isthen arranged so as to at least partially circumferentially surround thebase body. The base body is then at least partially disposed in therecess of the actuating element and forms the bottom of the blind hole.

According to another advantageous feature of the present invention, theactuating element may include at least one tongue-and-groove elementengaging with the actuating shaft body, in particular in form of aradial collar. The at least one tongue-and-groove element is providedfor, in particular, securely affixing the actuating element in theradial direction relative to the base body of the actuating shaft. Thetongue-and-groove element protrudes into the actuating shaft body so asto form a positive connection between the actuating element and theactuating shaft body. The tongue-and-groove element can be implementedas a radial collar extending outwardly in the radial direction.

According to another advantageous feature of the present invention, theactuating element may include at least one sealing element, inparticular implemented as a radial projection and/or aligned with theactuating shaft body in the radial direction. The sealing element isprovided to define the actuating shaft body in at least one directionduring manufacture of the actuating shaft. Such design of the actuatingelement is advantageous in particular when the second material of whichthe actuating shaft body is made is produced with an injection moldingprocess, because then there is no need for additional sealing measuresin the region of the actuating element. The sealing element may be, forexample, a radial projection.

According to yet another advantageous feature of the present invention,the sealing element may be aligned in the radial direction with theactuating shaft body. In other words, the sealing element of theactuating element may extend, starting from the base body or its center,in the radial direction approximately to the same distance as theactuating shaft body. The surface of the sealing element may be alignedwith the surface of the actuating shaft body at least in the regionwhere the actuating shaft body makes contact with the sealing element.

According to another advantageous feature of the present invention, atleast one cover element may be formed by the base body and/or theactuating shaft body. The cover element is used, as already describedabove, for covering or for uncovering a suction tube opening of thesuction tube arrangement. The cover element may be implemented as aflap. The cover element may be formed either by the base body, theactuating shaft body or a combination thereof. According to oneembodiment, the cover element may be formed by the actuating shaft body,wherein the second material may be selected to ensure an excellentsealing effect of the cover element. For attaining a good sealingeffect, a third material may be at least partially deposited on the basebody and/or the actuating shaft body, or on the cover element.Advantageously, the third material is an elastomer or a polymer.

The invention also relates to a method for producing an actuating shaftwith an actuating element for actuating the actuating shaft. Theactuating shaft may be produced from a base body made of a firstmaterial and an actuating shaft body made of a second material andapplied at least partially on the base body, wherein the actuatingelement is at least partially enclosed by the actuating shaft body. Themethod for producing an actuating shaft with an actuating element foractuating the actuating shaft includes the steps of providing the basebody and the actuating element, arranging the actuating element inrelation to the base body, and subsequently applying the second materialon the base body and the actuating element to form the actuating shaftbody. The second material is preferably applied with an injectionmolding process. When the actuating shaft is produced, the actuatingelements should be at least partially surrounded and overmolded with thesecond material.

According to an embodiment of the invention, application of theactuating shaft body on the base body and enclosing the actuatingelement are performed substantially simultaneously, in particular duringan injection molding process. Accordingly, no consecutive process stepsare implemented for forming the actuating shaft body and for attachingthe actuating element. Instead, this is performed during a singleprocess step which is preferably performed with an injection moldingprocess. The actuating shaft body is then molded on the base body sothat the position of the actuating element with respect to the base bodyis fixed.

BRIEF DESCRIPTION OF THE DRAWING

Other features and advantages of the present invention will be morereadily apparent upon reading the following description of currentlypreferred exemplified embodiments of the invention with reference to theaccompanying drawing, in which:

FIG. 1 shows a base body of an actuating shaft according to the presentinvention;

FIG. 2 shows the base body, an actuating element and an actuating shaftbody applied at least partially on the base body and the actuatingelement, according to the present invention; and

FIG. 3 shows a detailed cross-sectional view of the actuating shaft inthe region of the actuating element.

DETAILED DESCRIPTION OF PREFERRED EMBODIMENTS

Throughout all the figures, same or corresponding elements may generallybe indicated by same reference numerals. These depicted embodiments areto be understood as illustrative of the invention and not as limiting inany way. It should also be understood that the figures are notnecessarily to scale and that the embodiments are sometimes illustratedby graphic symbols, phantom lines, diagrammatic representations andfragmentary views. In certain instances, details which are not necessaryfor an understanding of the present invention or which render otherdetails difficult to perceive may have been omitted.

Turning now to the drawing, and in particular to FIG. 1, there is shownan actuating shaft 1, wherein only a base body 2 of the actuating shaft1 and a bearing sleeve 3 are illustrated. The base body 2 is made, forexample, of metal, in particular steel. In the embodiment illustrated inFIG. 1, the base body 2 is shaped as a crankshaft and has at least one,in the illustrated embodiment, several regions 4 which are spaced from arotation axis 5 in the radial direction. The first process steps in amanufacturing process for manufacturing the actuating shaft 1 includeproviding the illustrated base body 2 and applying the at least onebearing sleeve on the base body 2.

FIG. 2 shows the actuating shaft 1 after additional steps of themanufacturing process. As can be seen, an actuating shaft body 6 is atleast partially applied on the base body 2. The actuating shaft body 6typically does not completely enclose the base body 2. Instead, regionsof the base body remain uncovered, in particular in the region of therotation axis 5. The actuating shaft body 6 forms cover elements 7 inthe regions 4 of the base body 2 which are spaced from the rotation axis5. These cooperate, for example, with suction tube openings disposed ina suction tube arrangement associated with the actuating shaft 1. Thecover elements 7 are used to either uncover or cover, i.e. close, thesuction tube openings.

To this end, the actuating shaft 1 can be moved to at least two rotationangle positions in a predetermined angular position range, wherein thesuction tube openings are closed by the cover elements 7 in the firstrotation angle position and uncovered in the second rotation angleposition. Advantageously, the actuating shaft 1 can be moved to anyrotation angle position within the angular range for adjusting coverageof the suction tube openings by the cover elements 7, in particular byclosed-loop control and/or open-loop control.

The actuating shaft body 6 is applied on the base body 2 so as toprovide a torque-proof connection therebetween. The actuating shaft body6 can also be used to secure the bearing sleeve 3 on the base body 2,with the actuating shaft body 6 at least partially enclosing the bearingsleeve 3, in particular on both sides of the bearing sleeve 3.

An actuating element 8 is provided for actuating the actuating shaft 1.In the present exemplary embodiment, the actuating element 8 is arrangedat one end of the base body 2 and in one of the regions 4, i.e., spacedfrom the rotation axis 5 in the radial direction. The actuating element8 has a ball-shaped head 9 which is, for example, constructed to beoperatively connected with a drive of the actuating shaft 1 via acoupling linkage. Accordingly, a torque from the drive can be applied tothe actuating shaft 1 via the actuating element 8, wherein the torquecauses the actuating shaft 1 to rotate to the desired rotation angleposition. The actuating shaft 1 then rotates about its rotation axis 5.A support made, for example, of plastic for the actuating shaft 1 isprovided in the region of the bearing sleeve 3. The bearing sleeve 3 isplaced for support in an unillustrated bearing seat, thereby forming aradial bearing for the actuating shaft 1.

FIG. 3 shows a detailed cross-sectional view of the actuating shaft 1 inthe region of the actuating element 8. As can be clearly seen, theregion of the base body 2 projects into a recess 10 of the actuatingelement 8. Accordingly, the actuating element 8 at least partiallycircumferentially surrounds the base body 2. The recess 10 is formed soas to completely extend in the axial direction through the entireactuating element 8 and hence also through the ball-shaped head 9.However, the base body 2 does not completely extend through theactuating element 8 and the recess 10, respectively, so that a blindhole 11 formed by the recess 10 is disposed in the bail-shaped head 9. Abottom 12 of the blind hole 11 is defined by the base body of theactuating shaft 1, with the blind hole 11 being used, in particular, forcentering. Alternatively, the blind hole 11 may be closed afterinstallation of the actuating shaft 1, for example with a plug. Therecess 10 is advantageously dimensioned so as to clampingly hold thebase body 2 in the recess 10. This means that the inside dimensions ofthe recess 10 are at least slightly smaller than the outside dimensionsof the base body 2.

FIG. 3 also shows that the actuating element 8 is at least partiallyenclosed by the actuating shaft body 6. The actuating shaft body 6 is,for example, molded on the base body 2. The base body 2 is here made ofa first material, which may for example be a metal, whereas theactuating shaft body 6 is made of a second material which is inparticular a plastic. The second material is typically different fromthe first material.

To attain a reliable seat of the actuating element 8 on the actuatingshaft 1, the actuating element 8 has a tongue-and-groove element 13which engages with the actuating shaft body and may have the form of aradial collar. This prevents the actuating shaft body 6 from removingthe actuating element 8 from the base body 2. The tongue-and-grooveelement 13 also forms a tongue-and-groove connection with the actuatingshaft body 6. The tongue-and-groove element 13 is thus used to affix theactuating element 8 with respect to the base body in the axialdirection.

The actuating element 8 may additionally have a serration in the regionenclosed by the actuating shaft body 6, which serration extendssubstantially in the direction of the rotation axis 5 or at least at anangle to a circumferential direction. The actuating element is therebysafely affixed relative to the base body 2 also in the circumferentialdirection. Engagement of the base body 2 in the recess 10 of theactuating element 8 provides a lock in the radial direction. Theactuating element 8 is then securely held in all spatial directionsagainst displacement relative to the base body 2.

To simplify the manufacture of the actuating shaft 1, the actuatingelement 8 includes at least one sealing element 14, which delimits thelength of the actuating shaft body in the axial direction towards theball-shaped head 9. The sealing element 14 is hereby formed as a radialprojection. Preferably, the sealing element 14 or an outer circumference15 of the sealing element 14 is aligned with a surface 16 of theactuating shaft body 6. Alternatively, the outer circumference 15 of thesealing element 14 may also be enclosed by the actuating shaft body 6.

In the manufacture of the actuating shaft 1, application of theactuating shaft body 6 on the base body 2 and fixation of the actuatingelement 8 relative to the base body 2 may be performed essentiallysimultaneously, i.e. in a single process step. For this purpose, theactuating shaft body 6 may be applied on the base body 2 with aninjection molding process, with the actuating element 8 already beingplaced on the base body 2 ahead of time. In this way, an additionalprocess step which would otherwise be required for securing theactuating element 8 on the base body or the actuating shaft body 6 canbe eliminated. This enables a very cost-effective manufacture of theactuating shaft 1.

While the invention has been illustrated and described in connectionwith currently preferred embodiments shown and described in detail, itis not intended to be limited to the details shown since variousmodifications and structural changes may be made without departing inany way from the spirit and scope of the present invention. Theembodiments were chosen and described in order to explain the principlesof the invention and practical application to thereby enable a personskilled in the art to best utilize the invention and various embodimentswith various modifications as are suited to the particular usecontemplated.

What is claimed as new and desired to be protected by Letters Patent isset forth in the appended claims and includes equivalents of theelements recited therein:

1. An actuating shaft, in particular of a suction tube arrangement,comprising: an actuating element for actuating the actuating shaft, abase body made of a first material, and an actuating shaft body made ofa second material and at least partially applied on the base body, saidactuating shaft body at least partially enclosing the actuating element.2. The actuating shaft of claim 1, wherein the actuating elementcomprises a recess configured to at least partially receive the basebody, and wherein at least one region of the actuating element at leastpartially circumferentially surrounds the base body of the actuatingshaft.
 3. The actuating shaft of claim 2, wherein the actuating elementcomprises a ball-shaped head, and wherein the recess at least partiallyextends through the ball-shaped head.
 4. The actuating shaft of claim 1,wherein the first material is a metal.
 5. The actuating shaft of claim4, wherein the metal is steel.
 6. The actuating shaft of claim 1,wherein the second material is a plastic.
 7. The actuating shaft ofclaim 6, wherein the plastic comprises a polymer.
 8. The actuating shaftof claim 2, wherein the recess is a blind hole.
 9. The actuating shaftof claim 8, wherein a bottom of the blind hole is defined by the basebody.
 10. The actuating shaft of claim 1, wherein the actuating elementcomprises at least one tongue-and-groove element engaging in theactuating shaft body.
 11. The actuating shaft of claim 10, whereintongue-and-groove element is formed as a radial collar.
 12. Theactuating shaft of claim 1, wherein the actuating element comprises atleast one at least one sealing element.
 13. The actuating shaft of claim12, wherein the at least one sealing element is constructed as a radialprojection.
 14. The actuating shaft of claim 12, wherein the at leastone sealing element is aligned with the actuating shaft body in a radialdirection.
 15. The actuating shaft of claim 1, wherein the base body orthe actuating shaft body form at least one cover element.
 16. A methodfor producing an actuating shaft for actuating the actuating shaft,comprising the steps of: providing a base body from a first material andan actuating element, providing an actuating shaft body from a secondmaterial, at least partially applying the actuating shaft body on thebase body, and surrounding the actuating element at least partially withthe actuating shaft body.
 17. The method of claim 16, wherein the stepsof at least partially applying the actuating shaft body on the base bodyand at least partially surrounding the actuating element are performedsubstantially simultaneously.
 18. The method of claim 17, wherein thesteps are performed simultaneously in an injection molding process.